The present invention relates generally to testing and/or manufacturing.
A Functional Circuit Test (FCT) assesses a unit under test such as a printed circuit board assembly (PCBA). Typically, the unit under test is placed within a test fixture and connected to one or more testing circuits via electrical connectors. PCBAs usually include at least one receptacle block mounted thereon. The receptacle block contains one or more receptacles that engage the electrical connectors. The receptacles are coupled to components on the PCBA that are tested during the FCT.
Automated or manually operated systems urge the connectors toward and into the receptacle block so that an FCT can be conducted. To support and hold one or usually multiple electrical connectors, a typical test fixture includes a connector holder block. The system moves the connector holder block toward the PCBA so that the connectors enter the connector receptacle block simultaneously and engage the receptacles to enable the functional test of the PCBA.
When the connectors are inserted into the receptacle block in this manner, however, significant forces are applied to the receptacle block. The receptacle block typically deflects because of these insertion forces. Such deflection, especially if the connector block moves too great a distance toward the receptacle block, leads to stress in the PCBA and the electrical components that are mounted on it.
A common approach to address this problem employs a support that is moved into place behind the receptacle block. The support limits deflection and prevents over-stressing of the circuit board.
The test fixture may be configured so that the support, when placed in position behind the receptacle block, has a fixed location. This makes automatic positioning of the support easier. However, dimensional variability among different receptacle blocks creates concerns with this approach. If the receptacle block depth is smaller than that for which the support is configured, the support may be positioned too far back to provide needed support. Excessive deflection and stress to the PCBA may occur, leading to damage of the printed circuit board or components of the PCBA. If the connector block depth is greater than the connector block for which the support is configured, the support may interfere with the connector block as the support is moved into place, which may damage the PCBA or the PCBA-mounted receptacle block.
To accommodate different PCBA structures, a testing facility may need to readjust the position of the support each time production and testing change from one PCBA configuration to another. If the readjustment of conventional supports is not made when testing different PCBA configurations, the supports may be set with too much space between the support and the receptacle block, allowing too much deflection before providing support and preventing damage to the PCBA. Alternatively, if the conventional support is set too close to the receptacle block, and a too-large receptacle block is tested, interference between the support and the receptacle block may occur when the support block is moved into position. Such corrective readjustment, however, increases testing and production costs, and the amount of adjustment necessary may not be feasible in some instances.